Nonsmokers are exposed to nicotine given in the form of nicotine polacrilex gum; preliminary testing suggests that this formulation is of low abuse liability and is safe if given according to prescribed procedures. Two important experimental questions are addresed in this study. One concerns the further evaluation of the effects of nicotine polacrilex gum in nonsmokers to determine the possible effects of nicotine on cognitive performance in the absence of pre-existing nicotine dependence. Nicotine enhances performance in deprived smokers; however, it remains to be determined if nicotine dependence is a precondition for this effect. The second question is of general importance to the understanding of the development of drug dependence. Using a model of daily repeated voluntary cumulative dosing, the course of possible development of tolerance to the subjective, behavioral and physiologic actions of nicotine will be determined. Such data cannot be readily obtained with other drugs of abuse, and probably not with forms of nicotine known to be of high abuse liability (e.g., cigarettes), but may be safely collected following the procedures used in this study. Subject testing is completed (n=12) and data are currently being analyzed. Preliminary results indicate that nicotine did not enhance task performance and that tolerance to the effects of nicotine developed for some, but not all, measures. A preliminary report of the data was presented at the 1990 meeting of the Committee on Problems of Drug Dependence and a more complete report will be made at the 1991 meeting of the American Psychological Association.